This invention relates to a recorder in which a recording stylus is mounted on a moving body and repeatedly traverses the width of recording paper, wherein the paper is moved progressively lengthwise in a direction perpendicular to the direction of stylus scan. More in particular, the invention relates to a recorder having a recording stylus lead piece placed to extend over the upper edge of the recording paper in the stylus path, to prevent the recording paper from being torn or ripped.
Hereinafter, the present invention will be disclosed as embodied in the recorder of an underwater detection system, such as an echo sounder, although the invention is not limited to this type of system.
Recorders such as shown in FIGS. 1, and 2 have been proposed and widely used in echo sounding systems. Recorders shown in FIGS. 3 and 4 have been recently developed and unknown.
Referring to FIG. 1, a stylus assembly 1 comprises a conducting piece fastened to an endless belt 2. A recording stylus 3 is fixed to one end of the conducting piece, and a collector stylus 4 is fixed to the other end thereof. The collector stylus 4 slides along a contact rail 5 to which received echo signals are applied, while the recording stylus 3 moves across the width of electrically sensitive recording paper 6. In underwater detection systems, two types of electrically sensitive papers are often used. So-called dry paper consists of a very thin layer of metal (e.g. aluminum) covered with a conductive layer (e.g. carbon). When a current passes from a recording stylus through the conductive and metal layers to an electrically grounded metal roller or plate behind the paper, the upper layer is burnt away and the layer beneath it, which has a different color, then becomes visible. So-called moist paper produces a chemical change when a current passes through it from a stylus, so that discolouration becomes visible at the spot through which the current passes. The endless belt 2 extends around a driving pulley 7 and a driven pulley 8, and is driven at uniform speed by a motor through a reduction gear mechanism contained in a box 9, a driving shaft 10 and the driving pulley 7. The recording stylus 3 thus repeatedly moves across the recording paper 6, in synchronism with the sequence of the sonar signals transmitted in the water, so that a profile of the bottom of the sea and fish schools are recorded upon the paper 6. A pulling roller 12 is rotatably supported by parallel side plates 11, 11, the roller 12 being rotated by a suitable motor, via a gear mechanism. A pressing roller 13 is rotatably held by the plates 11 and mounted to press the recording paper against the pulling roller 12. A take-up reel 14 is rotatably supported by the plates 11 and driven by a motor. The recording paper is drawn from a paper roll mounted on a feed reel and advanced over a sending roller, a plate 15 horizontally maintained between the plates 11, and between the pulling and pressing rollers 12, 13, and is thence wound on the take-up reel 14. A recording stylus lead piece 16 is placed in the path of the stylus 3 extending over both of the plate 15 and the upper portion of the recording paper 6 sufficiently close thereto that it almost presses the paper 6 against the plate 15, so that the stylus can smoothly move onto the recording paper without causing any damage thereto.
Referring to FIG. 2, the top plate 15 is supported by the side plates 11 therebetween, and can be turned up around the axis of the pulling roller 12 in the direction of an arrow. A sending roller 18 is rotatably supported by the plate 15 at the right-hand end thereof. Suspension plates 19 extend downwardly from the side of the plate 15, to face each other. A feed reel 20 is rotatably supported between the suspension plates 19. Drive motor 21 for the driving pulley 7 and the pulling roller 12 are fixed to one of the plates 11. The recording paper 6 is drawn out of a paper roll mounted on the feed reel 20 over the roller 18, the plate 15 and the pulling roller 12, and is wound on the take-up reel 14. The recording stylus 3 moves across the recording paper 6 over the sending roller 18, which is electrically grounded. Currents dependent upon received echo signals flow from the stylus 3 to the roller 18 through the recording paper 6, so that corresponding marks or images are produced thereon. The recording stylus lead piece 16 is placed in the path of the recording stylus at the upper part of the sending roller 18.
When a new paper roll must be mounted on the feed reel positioned under the plate 15, the plate is turned up about the axis of the pulling roller 12 and held inclined as shown in FIG. 2.
Referring to FIGS. 3 and 4, in another recorder, each of the gears 23, 24 is fitted to one end of an axle rotatably supported by the plate 11. Each plate 25 or 26 is fixed at one end thereof to one of the axles, or to the side of one of the gears 23, 24. The sending roller 18 and the pulling roller 12 are respectively rotatably supported at the other ends by the plates 25, 26. Two pairs of suspension plates 27, 28 respectively are attached to extend downwardly from the sides of the plates 25, 26. The feed reel 20 and take-up reel 14 are respectively rotatably supported by the downwardly extending pairs of suspension plates 27, 28. The pressing roller 13 is rotatably supported by arms 29 pivoted to the plates 11, and are pulled rightward by a spring 30 to press the recording paper against the pulling roller 12. A lug 31 is fixed at one side of the plate 25. The recording paper is drawn from the paper roll mounted on the feed reel 20, and moves over the roller 18, the plates 25 and 26, and the roller 12, and is rewound on the take-up reel 14. The recording stylus lead piece is positioned in the path of the stylus 3.
When a new paper roll must be mounted in the recorder, the lug 31 is raised so that the plates 25, 26 respectively are turned up in the directions of arrows, and accordingly provide easy access to the feed and take-up reels 20, 14. After the end of the paper roll mounted on the feed reel 20 is drawn out over the rollers 18, 12 and engaged or fixed on the take-up reel 14, the lug 31 is depressed to lower the plates 25, 26, so that the recorder is restored to a normal writing operational mode.
The above described recorders must always keep the recording stylus in contact with the surface of the recording paper, in order to accurately depict underwater conditions. A spring is often utilized and incorporated in the stylus assembly to insure that the stylus always slides on the surface of the recording paper. Hence, if the recording stylus lead piece is not placed at an appropriate place, the stylus can hook the edge of the recording paper as it slides onto the paper. When dry paper is used, the recording stylus often draws the edge thereof to distort the shape of the paper, since the dry paper is strong and hard to tear. When moist paper is used, the stylus often tears or rips the paper. In order to prevent such damage from occuring, the above recorders have a thin flat piece attached to the plate 15 or to side plate 11, with its head portion curved in the path of the recording stylus, so that the flat piece extends over both the recording paper and the plate 15 or the sending roller 18. The recording stylus lead piece thus shaped as a curved thin flat piece is positioned so close to the plate 15 or the sending roller 18 that it almost presses the paper against the grounded backup member.
When an old paper roll is to be replaced by a new one in the recorders shown in FIGS. 1, 2, 3 and 4, after the plates 15, 25, 26 are turned up, some upper portion of the recording paper out of the new paper roll mounted on the feed reel must be passed between the recording stylus lead piece and the sending roller 18 or the plates 15, 25 and the front end of the paper must be fixed on the take-up reel 14. The plates 15, 25, 26 must then be lowered to restore the recorder to its normal condition. It often occurs, at the time of replacing a paper roll, that the new recording paper extends between the rollers over the recording stylus lead piece without the operator noticing the existence of the lead piece. This missetting of recording paper is realized only after the plates are lowered to their original positions, since the lead piece may easily be forgotten due to its position and size. This missetting of recording paper requires the operator to remove the newly-mounted paper, and to reinstall the paper in place. Such handling of lengthy paper is very troublesome, and the recording stylus lead piece is not easily utilized.
Accordingly, an object of the invention is to provide a recorder having a recording stylus lead piece, wherein a used paper roll can be easily replaced by a new one.
Another object of the invention is to provide a recorder having a recording stylus lead piece utilized in an underwater detection system, wherein a used paper roll can be easily replaced by a new one.
A further object of the invention is to provide a recorder in which a recording stylus lead piece is automatically withdrawn from the path of recording paper when the plate over which the recording paper passes is turned up, and is automatically returned to its original position closely over the paper when the plate is lowered, so that the recorder is restored to a normal writing operational mode.